You might notice that some email providers, especially Gmail, Hotmail, or a Microsoft web-based email service, display "on behalf of" in the sender details section of your messages. These messages are a direct result of email verification.
Whenever an email client sees bulk mail, they cross-check two addresses to determine if the messages are safe or not: the sender address and the address listed in the From field. The email client then compares the two addresses, and if there are differences, the email client may choose to display an "on behalf of" message to indicate that the author of the email wasn't necessarily the one sending the email. More specifically, recipients may see your information in the From field with a note that Sendloop sent the email on your behalf.
The best way to remove the "on behalf of" notices from your email is to:
DKIM and SPF are ways of proving your emails are legitimate and prompt the removal of "on behalf of" notices.
Please note, however, that some email clients may still display authentication notifications even after you set up SPF or DKIM. Such functionality is specific to the email client, and unfortunately, something over which Sendloop has no control.